Multifunctional magnetic nanoparticles modified with polyethylenimine and folic acid for biomedical theranostics

Conjugated Nanoparticles for Solid Tumor Theranostics: Unraveling the Interplay of Known and Unknown Factors

Cancer diagnoses have been increasing worldwide, and solid tumors are among the leading contributors to patient mortality, creating an enormous burden on the global healthcare system. Cancer is responsible for around 10.3 million deaths worldwide. Solid tumors are one of the most prevalent cancers observed in recent times. On the other hand, early diagnosis is a significant challenge that could save a person's life. Treatment with existing methods has pitfalls that limit the successful elimination of the disorder. Though nanoparticle-based imaging and therapeutics have shown a significant impact in healthcare, current methodologies for solid tumor treatment are insufficient. There are multiple complications associated with the diagnosis and management of solid tumors as well. Recently, surface-conjugated nanoparticles such as lipid nanoparticles, metallic nanoparticles, and quantum dots have shown positive results in solid tumor diagnostics and therapeutics in preclinical models. Other nanotheranostic material platforms such as plasmonic theranostics, magnetotheranostics, hybrid nanotheranostics, and graphene theranostics have also been explored. These nanoparticle theranostics ensure the appropriate targeting of tumors along with selective delivery of cargos (both imaging and therapeutic probes) without affecting the surrounding healthy tissues. Though they have multiple applications, nanoparticles still possess numerous limitations that need to be addressed in order to be fully utilized in the clinic. In this review, we outline the importance of materials and design strategies used to engineer nanoparticles in the treatment and diagnosis of solid tumors and how effectively each method overcomes the drawbacks of the current techniques. We also highlight the gaps in each material platform and how design considerations can address their limitations in future research directions.

Poly(ethylene-imine)-Functionalized Magnetite Nanoparticles Derivatized with Folic Acid: Heating and Targeting Properties

Magnetite nanoparticles (MNPs) coated by branched poly (ethylene-imine) (PEI) were synthesized in a one-pot. Three molecular weights of PEI were tested, namely, 1.8 kDa (sample MNP-1), 10 kDa (sample MNP-2), and 25 kDa (sample MNP-3). The MNP-1 particles were further functionalized with folic acid (FA) (sample MNP-4). The four types of particles were found to behave magnetically as superparamagnetic, with MNP-1 showing the highest magnetization saturation. The particles were evaluated as possible hyperthermia agents by subjecting them to magnetic fields of 12 kA/m strength and frequencies ranging between 115 and 175 kHz. MNP-1 released the maximum heating power, reaching 330 W/g at the highest frequency, in the high side of reported values for spherical MNPs. In vitro cell viability assays of MNP-1 and MNP-4 against three cell lines expressing different levels of FA receptors (FR), namely, HEK (low expression), and HeLa (high expression), and HepG2 (high expression), demonstrated that they are not cytotoxic. When the cells were incubated in the presence of a 175 kHz magnetic field, a significant reduction in cell viability and clone formation was obtained for the high expressing FR cells incubated with MNP-4, suggesting that MNP-4 particles are good candidates for magnetic field hyperthermia and active targeting.

Interfacial Structure and Interfacial Tension in Model Carbon Fiber-Reinforced Polymers

Carbon fiber-reinforced plastics (CFRPs) are widely used materials with outstanding mechanical properties. The wettability between the polymer matrix and carbon fiber in the interphase region significantly influences the strength of the composite. Sizing agents consisting of multiple components are therefore frequently applied to improve wetting and interfacial adhesion between polymers and carbon fiber in CFRPs. However, the complex compositions of sizing solutions make detailed interpretations of their impacts on interfacial wetting difficult. In this work, surface-sensitive sum frequency generation (SFG) spectroscopy was utilized to characterize the sizing/polymer and sizing/carbon fiber interfacial structures to gain molecular-level understandings of the wetting improvements afforded by sizing. A mixture sizing solution containing polyethylenimine (PEI, adhesion promoter) and Lutensol (surfactant) was investigated when contacting nylon (model plastics), polypropylene (model plastics), and graphite (model carbon fiber). Our results demonstrated that although the addition of the surfactant led to an interfacial tension decrease (in comparison to pure PEI solution) on nylon and polypropylene, the interfacial tension was surprisingly increased on graphite, contrasting with the commonly accepted function of surfactants. SFG characterizations revealed the multilayer molecular structures at these buried interfaces. The peculiar interfacial tension increase at the graphite/sizing interface was then correlated to the strong amine-π interactions between PEI and graphite. PEI was therefore demonstrated to be an effective adhesion promoter for carbon fiber. This article reports the first investigation of (polymer + surfactant) complex structures at solid-liquid interfaces. The valuable structural insights obtained by SFG analysis enable more accurate understandings of the composition-wettability (structure-function) relationship. These detailed understandings of interactions between sizing and the substrates promote more informed and optimized selections of sizing formulae.

Hyperthermia affects collagen fiber architecture and induces apoptosis in pancreatic and fibroblast tumor hetero-spheroids in vitro

Desmoplasia, an aberrant production of extracellular matrix (ECM), is considered as one predictive marker of malignancy of pancreatic cancer. In this paper, we study the effect of mild hyperthermia on fibrillary collagen architecture in murine Achilles tendons and in a pancreatic cancer model, in vitro, i.e. 3D hetero-type tumor spheroids, consisting of pancreatic cancer (Panc-1) cells and fibroblasts (WI-38), producing collagen fibers. We clearly demonstrate that i) mild hyperthermia (40 °C, 42 °C) damages the collagen architecture in murine Achilles tendons. ii) Mild extrinsic (hot air) and iron oxide nanoparticle based magnetic hyperthermia reduce the level of collagen fiber architecture in the generated hetero-type tumor spheroids. iii) Mild magnetic hyperthermia reduces cell vitality mainly through apoptotic and necrotic processes in the generated tumor spheroids. In conclusion, hetero-type 3D tumor spheroids are suitable for studying the effect of hyperthermia on collagen fibers, in vitro.

Development of Copper Nanoclusters for In Vitro and In Vivo Theranostic Applications

Theranostics refers to the incorporation of therapeutic and diagnostic functions into one material system. An important class of nanomaterials exploited for theranostics is metal nanoclusters (NCs). In contrast to gold and silver NCs, copper is an essential trace element for humans. It can be more easily removed from the body. This, along with the low cost of copper that offers potential large-scale nanotechnology applications, means that copper NCs have attracted great interest in recent years. The latest advances in the design, synthesis, surface engineering, and applications of copper NCs in disease diagnosis, monitoring, and treatment are reviewed. Strategies to control and enhance the emission of copper NCs are considered. With this synopsis of the up-to-date development of copper NCs as theranostic agents, it is hoped that insights and directions for translating current advances from the laboratory to the clinic can be further advanced and accelerated.

Exploiting the biomimetic and luminescence properties of multivalent dendrimer-semiconductor nanohybrid materials in the ultra-low level determination of folic acid

In view of the enhanced generation of folate receptors in cancerous cells and diseases linked to the deficiency of folic acid, such as anemia, mental devolution, congenital malformation, etc., the development of a simple method for the ultra-sensitive determination of folic acid remains a long-standing issue for practical applications in medicine and biotechnology. Thus, the proposed luminescence based strategy involving multifunctional poly(amidoamine) (PAMAM) dendrimer encapsulated quantum dots (QDs) as a probe provides a simple, fast and efficient method for the selective determination of folic acid at the nano-molar level. Absorption and Fourier transform infra-red (FTIR) spectroscopy provide evidence of the binding of folic acid with dendrimer amine groups. The emission quenching of dendrimer encapsulated CdS QDs follows a linear Stern-Volmer plot with an exceedingly high value of the Stern-Volmer constant (K_SV = 8.4 × 10⁶ M^-1) facilitating a higher detection efficiency. Similar quenching analysis with dendrimer-ZnS QDs showed a slightly lower Stern-Volmer constant (K_SV = 2.29 × 10⁶ M^-1). The lower probing efficiency of the protein or amino acid capping of QDs has been explained through zeta potential measurements. The solvent polarity dependence suggests a charge transfer process responsible for the emission quenching of CdS QDs, which is static in nature as revealed by lifetime measurements. The determination of folic acid at this low level is not affected by possible interfering molecules, such as vitamin C, vitamin B₁₂ and uric acid. Calorimetric measurements showed that the exothermic binding of folic acid with a dendrimer follows enthalpy-entropy compensation. The detailed mechanistic aspect of interactions of folic acid with the QD probe helps in a better understanding of the detection process, which in turn can assist in developing a dendrimer based material for image analysis and drug delivery in folate receptor rich cells.

Thermo-Magnetoresponsive Dual Function Nanoparticles: An Approach for Magnetic Entrapable-Releasable Chitosan

Magnetic polymeric nanoparticles can be used for selective binding in a magnetic field. However, as the magnetic nanoparticles (MAG) are stabilized with polymers, the separation of the MAG from the polymer chains after use is difficult. This work proposes a combination of a thermoresponsive polymer with MAG allows for the as-desired simple removal of MAG from the polymer chains. For this, chitosan (CS) was conjugated with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and antibody (Ab) together with the physisorbed MAG as a thermo-magneto dual functional material. The key synthesis steps are (i) radical polymerization of NIPAM in the presence of mercaptoacetic acid so that the PNIPAM obtained contains terminal carboxylic acid groups (PNIPAM-COOH), (ii) the CS-N-hydroxysuccinamide water-based system that allows conjugation of CS with PNIPAM-COOH in water at room temperature, and (iii) the weak interaction between MAG and the CS chain. As a model application, CS is conjugated with the antirecombinant Leptospirosis Ab (rLipL32) to allow the selective binding and collection of the target antigen under the dual functions. This is the first demonstration of a simple but effective solution for MAG exclusion from the target molecules and will be practical for diverse applications, such as diagnosis, sensors, filtration, etc.

Macrophages mediated diagnosis of rheumatoid arthritis using fibrin based magnetic nanoparticles as MRI contrast agents

BACKGROUND

A variety of bioimaging tools assists in the diagnosis and evaluation of rheumatoid arthritis (RA) and other osteoarthritis. However, detection of RA in the early stages by targeting its macrophages with suitable contrast agents will help in arresting the progression of the disease.

METHODS

In the present study, we investigated the effectiveness of using magnetic fibrin nanoparticles (MFNPs) conjugated with folic acid (FA-MFNPs) as a specific contrast agent to target the activated macrophages, which overexpress the folate receptors (FR) in the knee joints of rats with antigen-induced arthritis (AIA).

RESULTS

FA-MFNPs were spherical with an average size of 18.3±1.6nm. In vitro studies have shown effective internalization of FA-MFNPs into the Raw264.7 macrophage cells. In vivo studies were carried out by injecting FA-MFNPs intravenously into the arthritic rats. The results showed enhanced MR imaging in the synovium of arthritic joints. Prussian blue histological staining confirmed uptake of FA-MFNPs by macrophages in the synovial tissue.

CONCLUSION

The animal experiment results indicate that FA-MFNPs can be used as a specific MRI contrast agent in identifying phagocytic active macrophages in the synovial joints.

GENERAL SIGNIFICANCE

Blood is the precursor source for synthesising the fibrin-based iron oxide (magnetic) nanoparticles (MFNPs) with diameters between 12 and 15nm. It has excellent superparamagnetic behaviour, biocompatibility, osteogenic potency, hemocompatibility, and biodegradable properties. MFNPs-based nanocomposites might be a promising contrast agent for bioimaging.

Efficient Transfection by Using PDMAEMA-Modified SiNWAs as a Platform for Ca(2+)-Dependent Gene Delivery

The major bottleneck for gene delivery lies in the lack of safe and efficient gene vectors and delivery systems. In order to develop a much safer and efficient transfection system, a novel strategy of combining traditional Ca(2+)-dependent transfection with cationic polymer poly(N,N-dimethylamino)ethyl methacrylate (PDMAEMA) modified silicon nanowire arrays (SiNWAs) was proposed in this work. Detailed studies were carried out on the effects of the PDMAEMA polymerization time, the Ca(2+) concentration, and the incubation time of Ca(2+)@DNA complex with PDMAEMA-modified SiNWAs (SN-PDM) on the gene transfection in the cells. The results demonstrated that the transfection efficiency of SN-PDM assisted traditional Ca(2+)-dependent transfection was significantly enhanced compared to those without any surface assistance, and SN-PDM with polymerization time 24 h exhibited the highest efficiency. Moreover, the optimal transfection efficiency was found at the system of a complex containing Ca(2+) (100 mM) and plasmid DNA (pDNA) incubated on SN-PDM for 20 min. Compared with unmodified SiNWAs, SN-PDM has little cytotoxicity and can improve cell attachment. All of these results demonstrated that SN-PDM could significantly enhance Ca(2+)-dependent transfection; this process depends on the amino groups' density of PDMAEMA on the surface, the Ca(2+) concentration, and the available Ca(2+)@DNA complex. Our study provides a potential novel and excellent means of gene delivery for therapeutic applications.

Bone-targeted delivery of nanodiamond-based drug carriers conjugated with alendronate for potential osteoporosis treatment

This paper describes the design of alendronate-conjugated nanodiamonds (Alen-NDs) and evaluation of their feasibility for bone-targeted delivery. Alen-NDs exhibited a high affinity to hydroxyapatite (HAp, the mineral component of bone) due to the presence of Alen. Unlike NDs (without Alen), Alen-NDs were preferentially taken up by MC3T3-E1 osteoblast-like cells, compared to NIH3T3 and HepG2 cells, suggesting their cellular specificity. In addition, NDs itself increased ALP activity of MC3T3-E1 cells, compared to control group (osteogenic medium) and Alen-NDs exhibited more enhanced ALP activity. In addition, an in vivo study revealed that Alen-NDs effectively accumulated in bone tissues after intravenous tail vein injection. These results confirm the superior properties of Alen-NDs with advantages of high HAp affinity, specific uptake for MC3T3-E1 cells, positive synergistic effect for ALP activity, and in vivo bone targeting ability. The Alen-NDs can potentially be employed for osteoporosis treatment by delivering both NDs and Alen to bone tissue.

Hydrophilic Magnetite Nanoparticles Enhance Anticancer Activity of Anthracyclines In Vitro

A novel method for enhancing the anticancer activity of anthracyclines in vitro was proposed by using hydrophilic magnetic nanoparticles. Citric acid-coated magnetite nanoparticles Fe3O4 (nano-Fe3O4-CA) interacted with anthracyclines by electrostatic and hydrophobic forces, resulting in the formation of aggregates (nano-Fe3O4-CA-drug). The aggregate was studied by resonance light scattering and fluorescence spectroscopy. The results indicated that in comparison with anthracyclines, the nano-Fe3O4-CA-drug showed high activity towards incorporation in the DNA chain. Furthermore, the cytotoxicity of nano-Fe3O4-CA-drug was investigated by cytotoxicity experiment and cell morphology study. The results confirmed that the nano-Fe3O4-CA-drug could inhibit the growth of cells more effectively than the drug alone. In conclusion, usage of nano-Fe3O4-CA affords reduction of the dosage of anthracyclines in vitro.

Facile synthesis of chitosan assisted multifunctional magnetic Fe3O4@SiO2@CS@pyropheophorbide-a fluorescent nanoparticles for photodynamic therapy

Chitosan assisted magneto-fluorescence nanoparticle Fe₃O₄@SiO₂@CS@PPA is a potential photosensitizer for simultaneous PDT and medical fluorescence imaging.

Preparation, characterization and in vitro photodynamic therapy of a pyropheophorbide-a-conjugated Fe3O4 multifunctional magnetofluorescence photosensitizer

Core–shell structure magneto-fluorescence chlorin pyropheorbide-a photosensitizer (MFNPs) with good water-dispersity and strong superparamagnetic for photodynamic therapy.

A bimodal molecular imaging probe based on chitosan encapsulated magneto-fluorescent nanocomposite offers biocompatibility, visualization of specific cancer cells in vitro and lung tissues in vivo

Multifunctional hybrid nanocomposite material, consists of chitosan encapsulated iron oxide (as MRI contrasting agent), CdS (as fluorescent probe) nanoparticles and podophyllotoxin (as anticancer drug) was synthesized and characterized. The TEM studies suggested the size of the NPs to be in the range of 80-100 nm. These nanocomposites were treated with different cancer cell lines viz., KB, C6 and A549 cells. Fluorescence imaging and Perl's Prussian blue staining confirmed the presence of these nanocomposites inside both KB and C6 cells but not in A549 cells. Cytotoxicity experiments revealed that these biopolymer coated nanocomposites showed minimal toxicity towards cancerous cells. Further the intraperitoneal administration of one of the nanoformulations to Wistar rats suggested deposition of these nanocomposites in the lungs. The hematological, biochemical and histopathological analysis confirmed that these nanocomposites are safe to use as a novel dual mode imaging material.

Drug-conjugated polymers as gene carriers for synergistic therapeutic effect

The ability to safely and effectively transfer gene into cells is the fundamental goal of gene delivery. In spite of the best efforts of researchers around the world, gene therapy has limited success. This may be because of several limitations of delivering gene which is one of the greatest technical challenges in the modern medicine. To address these issues, many efforts have been made to bind drugs and genes together by polymers for co-delivery to achieve synergistic effect. Usually, binding interaction of drugs with polymers is either physical or chemical. In case of drug-polymer physical interaction, the efficiency of drugs generally decreases because of separation of drugs from polymers in vivo whenever it comes in contact with charged biofluid/s or cells. While chemical interaction of drug-polymer overcomes the aforementioned obstacle, several problems such as steric hindrance, solubility, and biodegradability hinder it to develop as gene carrier. Considering these benefits and pitfalls, the objective of this review is to discuss the possible extent of drug-conjugated polymers as safe and efficient gene delivery carriers for achieving synergistic effect to combat various genetic disorders.

Novel delivery approaches for cancer therapeutics

Currently, a majority of cancer treatment strategies are based on the removal of tumor mass mainly by surgery. Chemical and physical treatments such as chemo- and radiotherapies have also made a major contribution in inhibiting rapid growth of malignant cells. Furthermore, these approaches are often combined to enhance therapeutic indices. It is widely known that surgery, chemo- and radiotherapy also inhibit normal cells growth. In addition, these treatment modalities are associated with severe side effects and high toxicity which in turn lead to low quality of life. This review encompasses novel strategies for more effective chemotherapeutic delivery aiming to generate better prognosis. Currently, cancer treatment is a highly dynamic field and significant advances are being made in the development of novel cancer treatment strategies. In contrast to conventional cancer therapeutics, novel approaches such as ligand or receptor based targeting, triggered release, intracellular drug targeting, gene delivery, cancer stem cell therapy, magnetic drug targeting and ultrasound-mediated drug delivery, have added new modalities for cancer treatment. These approaches have led to selective detection of malignant cells leading to their eradication with minimal side effects. Lowering multi-drug resistance and involving influx transportation in targeted drug delivery to cancer cells can also contribute significantly in the therapeutic interventions in cancer.

Folate-conjugated nanoparticles as a potent therapeutic approach in targeted cancer therapy

The selective and efficient drug delivery to tumor cells can remarkably improve different cancer therapeutic approaches. There are several nanoparticles (NPs) which can act as a potent drug carrier for cancer therapy. However, the specific drug delivery to cancer cells is an important issue which should be considered before designing new NPs for in vivo application. It has been shown that cancer cells over-express folate receptor (FR) in order to improve their growth. As normal cells express a significantly lower levels of FR compared to tumor cells, it seems that folate molecules can be used as potent targeting moieties in different nanocarrier-based therapeutic approaches. Moreover, there is evidence which implies folate-conjugated NPs can selectively deliver anti-tumor drugs into cancer cells both in vitro and in vivo. In this review, we will discuss about the efficiency of different folate-conjugated NPs in cancer therapy.

Multimodal theranostic nanomaterials derived from phthalocyanine-based organic salt

This study represents a one pot simplistic approach towards development of multimodal theranostic nanomaterials.

Enhancement of cancer specific delivery using ultrasound active bio-originated particles

A bio-available microbubble, liposome, and Fe³⁺ chelated melanin nanoparticle complex with a dual ultrasound and T₁-w magnetic resonance imaging modality has been synthesized for the specific targeting of cancer cells.

Bioconjugated iron oxide nanocubes: synthesis, functionalization, and vectorization

A facile bottom-up approach for the synthesis of inorganic/organic bioconjugated nanoprobes based on iron oxide nanocubes as the core with a nanometric silica shell is demonstrated. Surface coating and functionalization protocols developed in this work offered good control over the shell thickness (8-40 nm) and enabled biovectorization of SiO2@Fe3O4 core-shell structures by covalent attachment of folic acid (FA) as a targeting unit for cellular uptake. The successful immobilization of folic acid was investigated both quantitatively (TGA, EA, XPS) and qualitatively (AT-IR, UV-vis, ζ-potential). Additionally, the magnetic behavior of the nanocomposites was monitored after each functionalization step. Cell viability studies confirmed low cytotoxicity of FA@SiO2@Fe3O4 conjugates, which makes them promising nanoprobes for targeted internalization by cells and their imaging.

Delivering colloidal nanoparticles to mammalian cells: a nano-bio interface perspective

Understanding the behavior of multifunctional colloidal nanoparticles capable of biomolecular targeting remains a fascinating challenge in materials science with dramatic implications in view of a possible clinical translation. In several circumstances, assumptions on structure-activity relationships have failed in determining the expected responses of these complex systems in a biological environment. The present Review depicts the most recent advances about colloidal nanoparticles designed for use as tools for cellular nanobiotechnology, in particular, for the preferential transport through different target compartments, including cell membrane, cytoplasm, mitochondria, and nucleus. Besides the conventional entry mechanisms based on crossing the cellular membrane, an insight into modern physical approaches to quantitatively deliver nanomaterials inside cells, such as microinjection and electro-poration, is provided. Recent hypotheses on how the nanoparticle structure and functionalization may affect the interactions at the nano-bio interface, which in turn mediate the nanoparticle internalization routes, are highlighted. In addition, some hurdles when this small interface faces the physiological environment and how this phenomenon can turn into different unexpected responses, are discussed. Finally, possible future developments oriented to synergistically tailor biological and chemical properties of nanoconjugates to improve the control over nanoparticle transport, which could open new scenarios in the field of nanomedicine, are addressed.

Current progress in gene delivery technology based on chemical methods and nano-carriers

Gene transfer methods are promising in the field of gene therapy. Current methods for gene transfer include three major groups: viral, physical and chemical methods. This review mainly summarizes development of several types of chemical methods for gene transfer in vitro and in vivo by means of nano-carriers like; calcium phosphates, lipids, and cationic polymers including chitosan, polyethylenimine, polyamidoamine dendrimers, and poly(lactide-co-glycolide). This review also briefly introduces applications of these chemical methods for gene delivery.

Luminescent magnetic hollow mesoporous silica nanotheranostics for camptothecin delivery and multimodal imaging

The synthesis of a novel and specific nanoplatform for anticancer drug delivery, fluorescence imaging and contrast agent in magnetic resonance imaging has been described.